Twin air-pump.



No. 871,114. PATENTED NOV. 19, 1907.

w. A. DREWBTT.

TWIN AIR PUMP.

APPLICATION FILED JAN-25,1904.

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PATENTED NOV. 19, 1907.

W. A. DRBWBTT. TWIN AIR PUMP. APPLICATION FILED .IAN.25,1904.

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W. A. DREWETT.

TWIN AIR PUMP.

APPLICATION FILED .TAN.25, 1904.

PATENTED NOV. 19, 1907.

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UNITED STATES PATENT OFFICE.

WILLIAM A. DREWETT, OF NEW YORK, N. Y., ASSIGNOR TO MARSHALL '1.DAVIDSON, OF

BROOKLYN, NEW YORK.

TWIN AIR-PUMP.

Specification of Letters Patent.

Patented Nov. 19, 1907'.

Appli ation fil d January 25,190 Serial No. 190.556.

To all whom it may concern:

Be it'known that 1, WILLIAM A. DREW- ETT, a citizen of the UnitedStates, and resident of the borough of Brooklyn, in the city and Stateof New York, have invented a new and useful Twin Air-Pump, of which thefollowing is a specification.

My invention relates to twin air pumps, with the object in view ofimproving the structure of the steam cylinder supports and providingmeans for steadying the piston rods, simplifying the access to theinterior of the air cylinders and for practically decreasing thedistance between the air cylinders.

In the accompanying drawings, Figure 1 is a view of the pump in frontelevation, onehalf in section, Fig. 2 is an end view, Fig. 3 is avertical central section from front to rear, Fig.4 is a horizontalsection in the plane of the line A-A of Fig. 1, and Fig. 5 is a top planview in detail of the inner air cylinder head.

The air cylinders are denoted by 1 and 2. They are fitted at their upperand lower ends tothe walls of circular openings in upper and lowerhollow castings denoted by 3 and 4.. The casting 1 forms the base of thepump and the casting 3 forms a support for the superstructure whichcarries the steam cylinders, one for each air cylinder, the walking beamfor connecting the two piston rods and the guides for holding the pistonrods in right lines during their reciprocatory movements. The basecasting 4 is provided with step-shaped diaphragms, one at the base ofeach air cylinder, denoted by 5 (Fig. 1), car rying the air inlet valves6 and an air inlet opening 7 is common to the two cylimlers. The castin3 at the tops of the air cylinders is provided with an air deliveryopening 8 v common to the two air cylinders and each air cylinder isprovided at its upper end with a two-part or sectional head, the twoparts being substantially half sections and denoted by 9 and 10. Thesehalf sections are provided with flanges 1]., 12, projecting upwardly attheir meeting edges, for the reception of bolts 13 for securing thesections together in assembled adjustment.

The head 9, 10, is provided with the proper number of air outlet valvesfor transmitting the air from the cylinder to the interior of thecasting 3. The casting 3 is further provided at its upper wall withheads, one for each cylinder and located above and arranged to coactwith the inner heads hereinabove referred to. These upper or outerheadsare like the inner heads, each made sectional, the two half-sections ofone of the heads being denoted by 14, 15, (see Fig. 4) and are providedwith upwardly or outwardly extending flanges 16, 17, at their meetingedges for receiving bolts '18 to hold the sections in assembledadjustment. The hub of the inner head 9, 10, is shouldered as shown at19 (Fig. 1) for receiving the lower end of the hub 20 of the outer head,and the upper end of the hub of the inner head forms the lower gland forholding the packing 21 between it and the upper gland 22.

The frame-work for supporting the steam cylinders and operating partsabove the air cylinders, consists of four legs arranged in pairs, themembers 23, 2 1, of one pair extending upwardly from the casting 3 atthe 'front and rear of the casting in the central transverse plane ofthe cylinder 1 and gradually converging, and the members 25, 26, of theother pair extending in a corresponding manner upward in the centraltransverse plane of the cylinder 2. A cap plate 27 is secured lirmly tothe upper ends of the said legs and side girders 28, 29, bind the legsagainst a rocking motion in a longitudinal direction of the frame-work.A centrally located tie-rod 30, extends transversely through the girders28, 29, to hold the latter against vibration. The spread of the membersof each pair of legs 23, 2 1, and 25, 26, at their lower extremities issuch that the outer heads 14, 15, may be readily manipulated withoutdisturbing adjacent parts, while the sectional structure of the heads,both outer and inner, provides for their removal without disturbing thepiston rod.

The steam cylinders are denoted by 31, 32, and are mounted on the capplate 27 with their axes in alinement with the axes of the cylinders 1and 2, respectively. Each steam cylinder has its valve chambercontaining steam inlet and exhaust valves, the valves in the twochambers being connected to move together as is usual. The valvechambers are denoted by 33, 34. A piston 35 in the steam cylinder 31 isconnected by a piston rod 36 with a piston 37 in the air cylinder 1, thelatter being provided with air transmission valves 38 as is usual. Inlike manner a piston in the steam cylinder 32 is connected with a valvedpiston in the air cylinder 2 by a piston rod 39.

The piston rods 36 and 39 are connected by a rocking beam 40, termed,for convenpiston rods 36 and 39, one pair to each, and r are caused totravel in a rightline by means of a sliding cross head 45, one for eachpiston rod, which cross head has a sliding engagement with fixed uprightWays 46, 47, secured, respectively, to the inner sides of the legs 23,24. In like manner, the ways 48, 49, control the cross head attached tothe piston rod 39. This means for connecting the piston rods and holdingthem against lateral thrust, makes it feasible to locate the aircylinders in close proximity and so shorten the walking beam. The valveoperating rod 50, is connected with and operated by the walking beam 40as usual.

The converging arrangement of the legs or posts of the superstructureact as lateral braces while the location of the girders above the footof the superstructure leaves the top of the upper casting 3 free andaccessible and, at the same time, the frame is light and attractive.

What I claim is 1. The combination with the air and steam cylinders andtheir piston rods, of inner heads for the air cylinder provided with.discharge valves and outer sectional heads for the air cylindersarranged to coact with the inner heads 'to form an air-tight closurewhereby access may be gained to the pistons without removing oruncoupling the piston rods.

3. The combination with the air and steam cylinders and their pistonrods, of inner sectional heads for the air cylinders and outer sectionalheads for said cylinders, the said outer sectional heads havingtheirhubs interlocked with the hubs of the inner sectional heads to forman air-tight closure whereby access may be obtained to the pistonswithin the cylinders without removing or uncoupling the piston rods.

In testimony, that I claim the foregoing as my invention, I have signedmy name in presence of two witnesses, this 5th day of January 1904.

WM. A. DREWVETT. IVitnesses':

FREDK. HAYNEs, HENRY THIEME.

